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Chinese scientists discover first photocathode quantum materials

CGTN| Updated: March 30, 2023 L M S


Screenshot of the study published on Nature magazine, March 8, 2023.

A group of Chinese scientists discovered a new class of photocathode quantum materials from a reconstructed surface of strontium titanate (SrTiO3), the first of its kind in the world, according to a press release issued by the team's affiliated institution on Friday.

The team, from Westlake University in east China's Zhejiang Province, discovered unusual photoemission properties of a reconstructed surface of SrTiO3(100) single crystals prepared by simple vacuum annealing that go beyond the existing theoretical descriptions, said its study published in Nature magazine on March 8, 2023. 

A photocathode is an engineered surface that can convert light, or a beam of particles, into electrons through the photoelectric effect – one of the legacies of Albert Einstein. It sets a critical foundation for many modern technologies that rely on light detection or electron-beam generation. Photocathode materials have become core elements for many cutting-edge devices such as particle accelerators, free electron lasers, ultrafast electron microscopes and high-resolution electron spectrometers.

The theory has been long-standing and the currently existing photocathodes were mostly discovered six decades ago, according to He Ruihua, the leader of the research team who's also a tenure at Westlake University. 

However, progress in this rather matured field has been limited to refinements in photocathode performance based on sophisticated materials engineering that does not come cheap. Innovation in this field can only be approached by finding new surface material or bringing in an original theory.


A figure demonstration that compares the electron beams emitted from conventional materials (a) and the photocathode quantum material strontium titanate (b). /Westlake University

The discovery of the SrTiO3(100) single crystals, a commonly used material among similar physics laboratories, is considered a breakthrough in the industry.

This discovery is deemed important "not because it added a new property to the SrTiO3(100) single crystals, but the property itself could change the long-entrenched rules of the game, that it could relaunch the generally accepted as a well-developed field of photocathode technology," said Zheng Changxi, co-writer of the study and a researcher at the School of Science at Westlake University.

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